bug#45042: 27.1; emacs -nw on Windows does not always update cursor position on screen

[Eli Zaretskii]

> From: Ed Avis <ed.avis@qmaw.com>
> CC: "larsi@gnus.org" <larsi@gnus.org>,
>  "45042@debbugs.gnu.org"<45042@debbugs.gnu.org>
> Date: Mon, 25 Jan 2021 08:00:00 +0000
> 
> The problem with the cursor movement not updating doesn't just happen under 
> Alacritty.  I can also
> reproduce it using an ssh server on Windows, by sshing to the machine and 
> running emacs -nw.  The ssh
> client can be PuTTY or the Windows port of OpenSSH running in the Windows 
> command prompt.  Unsetting
> TERM does not appear to make a difference in any of these cases.

PuTTY emulates a Unix terminal with terminfo database, and thus
expects the program to send escape sequences to move the cursor.  If
the OpenSSH client used by Windows does the same, then it means these
two emulators aren't currently supported by Emacs on Windows, because
Emacs assumes a native Windows console.

Patches to add support for curses-like escape sequences are welcome.